package api_test

import (
	"bytes"
	"context"
	"database/sql"
	"encoding/json"
	"io"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"testing"

	"wh/api"
	"wh/config"
	"wh/runner"
	"wh/sim"
	"wh/store"
	"wh/vm"
)

func TestEndToEnd(t *testing.T) {
	ctx := context.Background()
	cfg := config.Default()
	cfg.AsteroidCount = 20

	// Set WH_TEST_PG to a postgres:// URL to run this against PostgreSQL
	// (its public schema is wiped first).
	dsn := "sqlite:" + filepath.Join(t.TempDir(), "t.db")
	if pg := os.Getenv("WH_TEST_PG"); pg != "" {
		db, err := sql.Open("pgx", pg)
		if err != nil {
			t.Fatal(err)
		}
		if _, err := db.Exec("DROP SCHEMA public CASCADE; CREATE SCHEMA public"); err != nil {
			t.Fatal(err)
		}
		db.Close()
		dsn = pg
	}
	st, err := store.Open(dsn)
	if err != nil {
		t.Fatal(err)
	}
	defer st.Close()
	if err := st.Migrate(ctx); err != nil {
		t.Fatal(err)
	}
	srv := httptest.NewServer(api.New(st, cfg))
	defer srv.Close()

	var key string
	do := func(method, path string, body []byte, want int) []byte {
		t.Helper()
		req, _ := http.NewRequest(method, srv.URL+path, bytes.NewReader(body))
		if key != "" {
			req.Header.Set("Authorization", "Bearer "+key)
		}
		resp, err := http.DefaultClient.Do(req)
		if err != nil {
			t.Fatal(err)
		}
		defer resp.Body.Close()
		b, _ := io.ReadAll(resp.Body)
		if resp.StatusCode != want {
			t.Fatalf("%s %s: status %d want %d: %s", method, path, resp.StatusCode, want, b)
		}
		return b
	}

	var reg struct {
		APIKey string `json:"api_key"`
		ShipID int64  `json:"ship_id"`
	}
	json.Unmarshal(do("POST", "/register", []byte(`{"name":"ann"}`), 201), &reg)
	do("POST", "/register", []byte(`{"name":"ann"}`), 409)
	do("GET", "/me", nil, 401)
	key = reg.APIKey
	ship := "/ships/" + itoa(reg.ShipID)

	// Launch needs a program first; program limits are enforced.
	do("POST", ship+"/launch", nil, 409)
	do("PUT", ship+"/program", []byte{1, 2, 3}, 400)
	do("PUT", ship+"/program", make([]byte, cfg.ProgramBytes+4), 413)

	// Echo the uplink back on the downlink, then idle.
	prog, err := vm.Assemble(`
		.equ TX 1024
		in r1, 0x70
		ldi r2, 0
		beq r1, r2, idle
		ldw r3, [r2]
		stw r3, [r2+TX]
		out 0x70, r1
	idle:
		yield
		jmp idle
	`)
	if err != nil {
		t.Fatal(err)
	}
	do("PUT", ship+"/program", prog, 204)
	do("PUT", ship+"/uplink", []byte("hi"), 409) // not launched yet
	do("POST", ship+"/launch", nil, 202)
	do("PUT", ship+"/program", prog, 409) // frozen once launching
	do("PUT", ship+"/uplink", []byte("PING"), 204)
	do("PUT", ship+"/uplink", make([]byte, cfg.CommBytes+1), 413)
	do("GET", ship+"/downlink", nil, 404)

	res, err := runner.RunNextDay(ctx, st, cfg)
	if err != nil {
		t.Fatal(err)
	}
	if res.Day != 0 {
		t.Fatalf("first run should be day 0, got %d", res.Day)
	}
	if b := do("GET", ship+"/downlink", nil, 200); len(b) != cfg.CommBytes || string(b[:4]) != "PING" {
		t.Fatalf("downlink = %q", b[:8])
	}
	var ships []struct{ Status string }
	json.Unmarshal(do("GET", "/ships", nil, 200), &ships)
	if len(ships) != 1 || ships[0].Status != store.StatusActive {
		t.Fatalf("ships = %+v", ships)
	}
	do("GET", "/market", nil, 200)

	// A second day from the persisted snapshot must match an uninterrupted
	// in-memory run: persistence may not change the simulation.
	res2, err := runner.RunNextDay(ctx, st, cfg)
	if err != nil {
		t.Fatal(err)
	}
	mem := sim.NewState(cfg)
	in := sim.DayInput{
		Launches: []sim.Launch{{ShipID: reg.ShipID, Owner: 1, Program: prog}},
		Uplinks:  []sim.Uplink{{ShipID: reg.ShipID, Data: []byte("PING")}},
	}
	var want sim.DayResult
	for d := 0; d < 2; d++ {
		if want, err = mem.RunDay(cfg, in); err != nil {
			t.Fatal(err)
		}
		in = sim.DayInput{}
	}
	if res2.Hash != want.Hash {
		t.Fatal("state after DB round-trip differs from in-memory run")
	}

	// Changing the config on an existing world is refused.
	cfg.Seed = 99
	if _, err := runner.RunNextDay(ctx, st, cfg); err == nil {
		t.Fatal("expected config mismatch error")
	}
}

func itoa(n int64) string {
	b, _ := json.Marshal(n)
	return string(b)
}